Crumbs soldier gives dog (5)
I believe the answer is:
corgi
'dog' is the definition.
(I know that corgi is a type of dog)
'crumbs soldier' is the wordplay.
'crumbs' becomes 'cor' (both can be exclamations of shock).
'soldier' becomes 'GI' (GI can mean a US soldier).
'cor'+'gi'='CORGI'
'gives' acts as a link.
(Other definitions for corgi that I've seen before include "Cardigan or Pembroke dog" , "Toy car manufacturer" , "Welsh breen of dog" , "Dog of Welsh breed, royal favourite" , "found in the kennels" .)